Quad parabolic snowmobile ski

Abstract

The quad parabolic snowmobile ski is an elongated body having a top side, a bottom side, a tip at the front end, a rear end, a pair of symmetrically opposed ski parabolic cutting edges disposed longitudinally along the bottom of the ski, and a keel. The keel is attached to the bottom of the ski and has a central median ridge, i.e., a keel rail, a substantial portion of which protrudes below the bottom of the ski to form a central and longitudinal point of contact with the snow. The keel defines symmetrically opposed snow-funneling channels along the opposite sides of the central median ridge. Varying radii of curvature of the channels form parabolically-shaped channel outer sidewalls. Symmetrically opposed keel parabolic cutting edges are formed by contouring a keel body width to follow the contour of the parabolic shaped outer sidewalls at a constant cutting edge width.

1. A snowmobile ski, comprising an elongated body having:
 a top side; 
 a strut attachment block disposed on the top side; 
 a bottom side; 
 a front end forming a tip; 
 a rear end; 
 a pair of symmetrically opposed ski parabolic cutting edges formed on the bottom side; and 
 a keel formed on the bottom side, the keel having a central median ridge extending from the bottom side to form a central and longitudinal point of contact with snow and symmetrically opposed snow-funneling channels defined along opposite sides of the central median ridge, the channels having varying radii of curvature to form outer sidewalls having parabolic shapes, the sidewalls, excluding the tip region, being laterally closest to each other at a center region of the elongated body and laterally farthest apart from each other between the tip and a front portion of the strut attachment block, as well as towards the rear end, the keel following the contour of the parabolic shaped outer sidewalls at a constant cutting edge width to form parabolic keel cutting edges, the parabolic cutting edges being disposed longitudinally along the bottom of the ski from a region near the front end tip to a region near the rear end, and having vertices directed laterally towards a longitudinal axis of the ski. 
 
     
     
       2. The snowmobile ski according to  claim 1 , wherein the central median ridge has a first gradient disposed longitudinally proximate a rear section of the strut attachment block, the gradient lowering depth of the central median ridge measured from the elongated body. 
     
     
       3. The snowmobile ski according to  claim 1 , wherein the central median ridge extends to a maximum channel depth below the elongated body. 
     
     
       4. The snowmobile ski according to  claim 1 , wherein the radii of curvature of the channels vary as a function of sidewall longitudinal displacement from the front end tip so that the outer sidewalls are parabolically-shaped. 
     
     
       5. The snowmobile ski according to  claim 1 , wherein the elongated body is composed of a high tensile strength, shatter resistant material. 
     
     
       6. The snowmobile ski according to  claim 1 , wherein the front end and the rear end of said elongated body are upturned. 
     
     
       7. The snowmobile ski according to  claim 2 , wherein the central median ridge has a second gradient disposed longitudinally proximate the rear end of the ski, whereby the depth of the central median ridge measured from the elongated body is lowered to form a rear terminus of the central median ridge. 
     
     
       8. The snowmobile ski according to  claim 3 , wherein the outer sidewalls extend downward a distance less than the channel depth from the elongate body. 
     
     
       9. The snowmobile ski according to  claim 5 , wherein the elongated body is composed of a lightweight material. 
     
     
       10. The snowmobile ski according to  claim 5 , wherein the elongated body is composed of an abrasion resistant material. 
     
     
       11. The snowmobile ski according to  claim 5 , further comprising a flexible, durable coating disposed on the elongated body, the coating having a low coefficient of surface friction to provide reduced turning effort from steering inputs during use of the ski. 
     
     
       12. A snowmobile ski, comprising an elongated body having:
 a top side; 
 a strut attachment block disposed on the top side; 
 a bottom side; 
 a front end forming a tip; and 
 a rear end, the elongated body having a parabolically-shaped lateral curvature extending from a region proximate the rear end to a region located longitudinally between the strut attachment block and the tip of the front end; 
 a keel formed on the bottom side, the keel having a central median ridge extending from the bottom side to form a central and longitudinal point of contact with snow and symmetrically opposed snow-funneling channels along opposite sides of the central median ridge, the channels having varying radii of curvature to form outer sidewalls, the outer sidewalls following the lateral contour of the elongated body to form a pair of inner keel parabolic cutting edges and a pair of outer ski parabolic cutting edges. 
 
     
     
       13. The snowmobile ski according to  claim 12 , wherein the central median ridge has a first gradient disposed longitudinally proximate a rear section of the strut attachment block, the gradient lowering depth of the central median ridge measured from the elongated body. 
     
     
       14. The snowmobile ski according to  claim 12 , wherein the central median ridge extends to a maximum channel depth below the elongated body. 
     
     
       15. The snowmobile ski according to  claim 12 , wherein the radii of curvature of the channels vary as a function of sidewall longitudinal displacement from the front end tip so that the outer sidewalls are parabolically-shaped. 
     
     
       16. The snowmobile ski according to  claim 12 , wherein the front end and the rear end of said elongated body are upturned. 
     
     
       17. The snowmobile ski according to  claim 12 , wherein the elongated body is composed of a high tensile strength, shatter resistant material. 
     
     
       18. The snowmobile ski according to  claim 12 , further comprising a grab handle extending from a front section of the strut attachment block to wrap around the tip of the elongated body, the handle for grabbing onto the ski for transport, and for handling the ski when attaching the ski to, and removing the ski from, the snowmobile. 
     
     
       19. The snowmobile ski according to  claim 13 , wherein the central median ridge has a second gradient disposed longitudinally proximate the rear end of the ski, whereby the depth of the central median ridge measured from the elongated body is lowered to form a rear terminus of the central median ridge. 
     
     
       20. The snowmobile ski according to  claim 14 , wherein the outer sidewalls extend downward a distance less than the channel depth from the elongate body.